Intraspecific variation in immune gene expression and heritable symbiont density

• DOI: 10.1101/2020.12.17.420083
• Publication Date: 2020-12-22T19:40:32Z
• Authors: Holly L. Nichols; Elliott B. Goldstein; Omid Saleh Ziabari; Benjamin J. Parker
• Keywords: Acyrthosiphon pisum; Antigenic variation

A bstract Host genetic variation plays an important role in the structure and function of heritable microbial communities. Recent studies have demonstrated that insects use immune mechanisms to regulate symbionts. Here we test hypothesis symbiont density within hosts is linked intraspecific differences response harboring We show pea aphids ( Acyrthosiphon pisum ) bacterial endosymbiont Regiella insecticola (but not all other species symbionts) suppress expression key genes. then functionally link suppression with using RNAi. The aphid complex comprised multiple reproductively-isolated host plant-adapted populations. These ‘biotypes’ distinct patterns infections: for example, from Trifolium biotype are strongly associated . Using RNAseq, compare gene genotypes biotypes, experience no symbionts at lower densities. generated F1 hybrids between two biotypes found both intermediate hybrids. suggest this system, suppressing increase their density, but some adapted prevent order control numbers. specific suppressed by been previously combat pathogens aphids, thus work highlights system’s dual interacting beneficial harmful microbes. uthor S ummary Heritable microbes most including agriculturally medically relevant pests. Explaining distribution abundance natural populations critical understanding these interactions. This contributes our mechanistic model host-microbe symbiosis suggests more broadly insect responses a host-symbiont Our also antagonistic coevolution can play interactions even when transmitted vertically provide clear benefit hosts.